Dam fish! Genetic and ecological study of the Rönne å populations of Atlantic salmon (Salmo salar) and brown trout (Salmo trutta)
(2023) BION03 20221Degree Projects in Biology
- Abstract
- Anthropogenic activities such as hydropower exploitation have been one of the main drivers of anadromous fish biodiversity loss during the past century. This has led to genetic homogenization and to the reduction of positive mechanisms such as the “portfolio effect”. In this study we propose the first comprehensive analysis of the genetic differences in Salmo salar and Salmo trutta populations in the Rönne å catchment area, through the utilization of Restriction-site Associated DNA sequencing. This revealed the presence of several different populations of both species throughout the river. In particular, pairwise Fst values comparisons and DAPCs showed Atlantic salmon populations to be different between tributaries of the catchment area.... (More)
- Anthropogenic activities such as hydropower exploitation have been one of the main drivers of anadromous fish biodiversity loss during the past century. This has led to genetic homogenization and to the reduction of positive mechanisms such as the “portfolio effect”. In this study we propose the first comprehensive analysis of the genetic differences in Salmo salar and Salmo trutta populations in the Rönne å catchment area, through the utilization of Restriction-site Associated DNA sequencing. This revealed the presence of several different populations of both species throughout the river. In particular, pairwise Fst values comparisons and DAPCs showed Atlantic salmon populations to be different between tributaries of the catchment area. Brown trout populations were found to be different in locations upstream and downstream of the migration obstacles. Moreover, a Structure analysis showed slight intragenetic admixture of trout populations in a locality where a hydropower plant was already removed. I further addressed suggestions on how to handle future management actions, such as the removal of the powerplants impeding their migration in the river. We also addressed the lack of knowledge on the outcome of such conservation efforts and wish to spur further research on it, in order to best comprehend the genetic processes that will be involved once further migration obstacles will be removed. (Less)
- Popular Abstract
- Dam fish! Genetic and ecological analysis of salmonids in the Rönne å
We are currently living through the “sixth extinction” geological era. This means that human-driven loss of biodiversity is threatening ecosystems and species globally. However, loss of biodiversity is also linked to anthropogenic activities and hydropower exploitation that increase genetic similarities both between and within species. This process endangers the positive effects on stability provided by the presence of more species and populations in the same habitat.
Salmonids, like Atlantic salmon (Salmo salar) and brown trout (Salmo trutta), provide several positive functions to the environment and mankind. In fact, they are important predators, competitors, and... (More) - Dam fish! Genetic and ecological analysis of salmonids in the Rönne å
We are currently living through the “sixth extinction” geological era. This means that human-driven loss of biodiversity is threatening ecosystems and species globally. However, loss of biodiversity is also linked to anthropogenic activities and hydropower exploitation that increase genetic similarities both between and within species. This process endangers the positive effects on stability provided by the presence of more species and populations in the same habitat.
Salmonids, like Atlantic salmon (Salmo salar) and brown trout (Salmo trutta), provide several positive functions to the environment and mankind. In fact, they are important predators, competitors, and preys to different species. Moreover, salmonids are fish that migrate back and forth from the river where they are born to the sea. This spreads their positive effects in both environments, highlighting their importance. However, several studies have shown that Atlantic salmon and brown trout populations are decreasing in southern Sweden, particularly in the Rönne å river. These are the reasons behind the birth of the EU project Life Connects, which intends to remove migration obstacles, such as hydropower plants. This will free up more than 100 km of river habitat to the species and improve their and the whole ecosystem’s conditions. However, there is scarce scientific knowledge about the populations of Atlantic salmon and brown trout in the Rönne å river and its tributaries. Thus, we used a cost-effective genetic method, called RAD (Restriction-site Associated DNA) sequencing, to extract and analyze the DNA of the different populations of the two species of salmonids.
The study revealed the presence of several different populations of the two species in the tributaries of Rönne å. However no significant difference was found for Atlantic salmon between Rönne å and two nearby streams, namely Vegeå and Stensån. Still, our analysis showed genetic differences between populations of Atlantic salmon inhabiting Rönne å and two of its tributaries, Klövabäcken and Rössjöholmsån. Another population of the same species was found to inhabit two nearby streams, Pinnån and Bäljane å. These differences could be due to visual and compass-type recognition from the fish of each stream, however the lack of knowledge on this matter points towards the need for further studies analyzing the exact drivers of this “homing behaviour” (i.e. the capacity of fish to return to their natal river).
Moreover, populations of brown trout were found to be different in locations upstream and downstream of the migration obstacles that are planned to be removed. This is because the obstacles impede the passage of the fish, not giving them the possibility to mate and admix. Further, in one location where the obstacle has been removed since 2021, mild admixture of the downstream and upstream populations was detected. This indicates that, when the other obstacles will be removed, there is the possibility for the other populations to admix as well. This would reduce the total biodiversity of the stream but would increase diversity in the DNA of each individual of one population. However, the lack of literature on the matter does not allow for any definite answer. Therefore, further studies on the genetics of brown trout will be needed once the obstacles will be removed from Rönne å and its tributaries. This will likely result in novel findings that could help better understanding the genetic mechanisms involved in management actions like this.
Master’s Degree Project in Aquatic Ecology. 60 credits. 2023
Advisors: Johanna Sjöstedt and Anders Nilsson
Aquatic Ecology (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9114022
- author
- Di Giorgio, Flavio
- supervisor
- organization
- course
- BION03 20221
- year
- 2023
- type
- H2 - Master's Degree (Two Years)
- subject
- language
- English
- id
- 9114022
- date added to LUP
- 2023-05-05 12:26:45
- date last changed
- 2023-05-05 12:26:45
@misc{9114022,
abstract = {{Anthropogenic activities such as hydropower exploitation have been one of the main drivers of anadromous fish biodiversity loss during the past century. This has led to genetic homogenization and to the reduction of positive mechanisms such as the “portfolio effect”. In this study we propose the first comprehensive analysis of the genetic differences in Salmo salar and Salmo trutta populations in the Rönne å catchment area, through the utilization of Restriction-site Associated DNA sequencing. This revealed the presence of several different populations of both species throughout the river. In particular, pairwise Fst values comparisons and DAPCs showed Atlantic salmon populations to be different between tributaries of the catchment area. Brown trout populations were found to be different in locations upstream and downstream of the migration obstacles. Moreover, a Structure analysis showed slight intragenetic admixture of trout populations in a locality where a hydropower plant was already removed. I further addressed suggestions on how to handle future management actions, such as the removal of the powerplants impeding their migration in the river. We also addressed the lack of knowledge on the outcome of such conservation efforts and wish to spur further research on it, in order to best comprehend the genetic processes that will be involved once further migration obstacles will be removed.}},
author = {{Di Giorgio, Flavio}},
language = {{eng}},
note = {{Student Paper}},
title = {{Dam fish! Genetic and ecological study of the Rönne å populations of Atlantic salmon (Salmo salar) and brown trout (Salmo trutta)}},
year = {{2023}},
}